1. Field of the Invention
The invention hereinafter disclosed relates to a safety device utilized at a loading dock to prevent accidental or unauthorized moving of a parked vehicle away from the dock while the vehicle is being loaded or unloaded.
2. Description of Related Art
Various locking devices, such as disclosed in Hahn, et al. U.S. Pat. No. 4,443,150, have heretofore been utilized to retain a parked vehicle against a loading dock while the vehicle is being loaded or unloaded. While the locking device disclosed in the aforenoted patent is effective in restraining such parked vehicle, it nevertheless is possessed of certain shortcomings such as: a) it relies upon a manual upward pull to effect a locking engagement between the device and a safety bar, commonly referred to as an ICC bar which is disposed at the rear end of the vehicle and depends from the underside thereof; b) the adjustment of the device to an operative locking mode and an inoperative release mode requires the manual manipulation of a tool to effect engagement with certain portions of the device which under certain circumstances may be a frustrating, awkward or time-consuming operation; furthermore, the tool may become lost or misplaced; c) the means for locking the device in an operative mode may be adversely affected by snow, ice and debris; d) signal lights indicating whether the hook member is in an operative or inoperative mode must be manually actuated and e) there is no audible signal if the ICC bar cannot be engaged by the hook member.
Other locking devices besides that disclosed in U.S. Pat. No. 4,443,150, may be susceptible to being damaged by the vehicle when backing into a parked position adjacent the loading dock or they may be of complex and costly design and highly susceptible to malfunction.